Pulse wave velocity refers to the speed of propagation of mechanical waves that travel along the length of a blood vessel. One common example is a cardiac pulse wave generated by the contractions of the heart. If one were to take the pulse of a subject at two well separated locations along the same vessel, there would be a noticeable time delay. This delay results from the amount of time necessary for the cardiac pulse wave to travel the distance between the two locations.
It is well known that the speed of a mechanical wave is dependent on the physical properties of the medium supporting the wave. It has also been realized that pulse wave velocity can vary from point-to-point along a body lumen, such as a blood vessel and the like. It has been proposed that the variation of pulse wave velocity along the length of a blood vessel wall can be used to characterize the blood vessel and serve as an indicator of blood vessel health. Changes in vessel pathology can alter the mechanical properties effecting the velocity of the wave. For instance, variations in stiffness along the length of a vessel could cause changes in velocity. In the case of a cardiac pulse wave, the velocity of the wave can be dependent on the elastic characteristics of the blood vessel wall and surrounding tissue as well as the compressibility of the blood. Currently, however, intravascular diagnostic systems and techniques are not capable of measuring pulse wave velocity within a blood vessel.
Accordingly, systems and methods for measuring pulse wave velocity within a blood vessel with an intravascular device are needed.